include/asm-x86_64/alternative-asm.i - arm/linux-arm64-legacy - Git at Google

 #include <linux/config.h>

 #ifdef CONFIG_SMP
 	.macro LOCK_PREFIX
 1:	lock
 	.section .smp_locks,"a"
 	.align 8
 	.quad 1b
 	.previous
 	.endm
 #else
 	.macro LOCK_PREFIX
 	.endm
 #endif
	#include <linux/config.h>

	#ifdef CONFIG_SMP
	.macro LOCK_PREFIX
	1: lock
	.section .smp_locks,"a"
	.align 8
	.quad 1b
	.previous
	.endm
	#else
	.macro LOCK_PREFIX
	.endm
	#endif